The method of this invention is one particularly useful in the automated cutting of pattern pieces from sheet material in the general way shown by U.S. patent application Ser. No. 07/571,077, filed Aug. 21, 1990, now U.S. Pat. No. 5,042,339, entitled "Method and Apparatus For Cutting Successive Segments of Sheet Material With Cut Continuation", and U.S. patent application Ser. No. 07/681,555, filed Apr. 5, 1991, now U.S. Pat. No. 5,134,911, entitled "Method for the Interrupted Cutting of a Line in Sheet Material", wherein the sheet material to be cut and the related cutting marker are of relatively long length and wherein the sheet material is cut by progressively moving one bite of it to a cutting station having a length a number of times shorter than that of the marker, cutting lines in such one bite of the sheet material while it is at the cutting station, moving the next adjacent bite of the work material to the cutting station, cutting lines in the next bite while it is at the cutting station, and repeating such movement of successive bites of the sheet material and the cutting of them at the cutting station until the entire marker has been cut. In the cutting of pattern pieces from sheet material by such bite-by-bite cutting it often occurs that a pattern piece will have a portion of it falling into one bite and another portion falling into an adjacent bite so that one part of the pattern piece is cut at one time while the involved bite is at the cutting station and another portion of it is cut at a later time while the adjacent bite is at the cutting station.
Where portions of a marker line are cut at different times, as for example in the above-described cutting of a pattern piece having portions falling into bites of sheet material cut at different times, it is, of course, necessary to define a split point for the line, that is a point at which the cutting of the line is automatically interrupted and then later resumed to allow an intervening advancement of the work material. In the past such split points have usually been straightforwardly taken as being the points at which a dividing line between two successive bites intersects marker lines passing between those two bites. The split points determined in this way are, however, often ones not optimal for splitting purposes due to the involved marker lines having discontinuities or other special features, such as slit notches, V-notches and sharp corners, located at or very close to them.
To inhibit the possibility of threads or other parts of the sheet material remaining uncut at the position of a line split, it is desirable to continue the cutting motion a little bit past a split point before withdrawing the cutting tool from cutting engagement with the sheet material and to thereafter restart the cutting procedure at a point spaced slightly before the split point. In doing this it may also be desirable to veer the cutting tool slightly away from the marker line when ending and starting cuts at a split point to achieve a definite crossing of cut paths assuring the avoidance of uncut threads, as explained in the aforementioned patent application Ser. No. 07,681,555. This however lengthens the zone of the split and thereby increases the possibility of such zone including features of the marker line, such as notches and sharp corners, which are preferably avoided.
The general object of this invention is therefore to provide a method for determining the optimum locations of points for the splitting of marker lines which pass between adjacent bites in the bite-by-bite cutting of sheet material, such optimum split point locations being ones which in comparison to all possible locations are best spaced away from notches, sharp corners and other similar features of the involved marker lines to eliminate or reduce the possibility of such features interfering with the efficiency and cleanness of the cutting process.
A further object of the invention is to provide a method for bite-by-bite two-dimensional cutting of sheet material using the aforementioned split point location determining method.
Further objects and advantages of the invention will be apparent from the following description of a preferred embodiment of the invention and from the accompanying drawings and claims.